EPA approves Cape Cod water quality plan

The U.S. Environmental Protection Agency on Sept. 17 formally approved an updated Section 208 Water Quality Plan for Cape Cod.

The Baker administration had submitted the plan to reduce nitrogen pollution in June.

Excess nitrogen results in algal blooms, reduced ecological vitality, and loss of habitat for organisms. Degraded water quality threatens tourism, fishing, shellfisheries, and numerous recreational pursuits, which are the economic foundation of the Cape.

Past studies indicate that in order to restore the health of water bodies, nitrogen levels would have to be reduced by up to 87 percent.

The Cape’s plan focuses on shared systems, remediation and restoration of natural solutions such as wetlands, and reducing the amount of nitrogen coming from septic systems. For example, a town may choose a lower-cost remediation, such as dredging an inlet, which could remove up to 30 percent of the nitrogen in an embayment, before choosing to build a large sewer system and sewage treatment plant.

Because of the sandy soil on the Cape, nitrogen and phosphorus from septic systems easily moves through the ground into lakes, ponds and bays and is the leading cause of pollution on the Cape. Nitrogen and phosphorus cause excessive growth of algae, which diminishes the capacity of wetlands to naturally absorb excess nitrogen. The algae growth can rob fish of oxygen and sometimes leads to large fish kills.

The Cape Cod Commission developed and drafted the 208 Plan Update for Department of Environmental Protection review in March 2015. The commission recently recommended designating each of the 15 Cape towns as Waste Treatment Management Agencies. The WMAs will now be responsible for all of the nitrogen that enters the groundwater from land within their jurisdiction as well as local nitrogen allocations.